This example shows a hierarchical tree of kinases, a protein family classification, with the root labeled "Kinase" branching into families like AGC, Atypical, and CAMK, down to individual gene IDs. Built with d3.v5 and rendered in SVG, the code uses d3.tree(), d3.hierarchy(), and d3.linkHorizontal() to compute and draw the layout. A zoom behavior is attached via d3.zoom() for panning and scaling, while node labels display names and numeric IDs with depth-based font sizing and a text-shadow for readability.